added captureSelector() to readme [skip ci]

1 files changed, 8 insertions, 1 deletions

diff --git a/tests/README.screenshots.md b/tests/README.screenshots.md
index bcf35ba99d..b0189fe343 100644
--- a/tests/README.screenshots.md
+++ b/tests/README.screenshots.md
@@ -136,7 +136,14 @@ If you want to compare a screenshot against an already existing expected screens
         }, done);
     });
 
-`"OptionalPrefix"` will default to the name of the test.
+If you want to compare only parts (all content within an element / selector) of a page you can do the following:
+
+    it("should load correctly", function (done) {
+        expect.screenshot("screenshot_name").to.be.captureSelector("#content", function (page) {
+            page.load(url);
+        }, done);
+    });
+    
 
 ### Manipulating Pages Before Capture